Evaluation of possible prophylactic and therapeutic effect of mefloquine on experimental cryptosporidiosis in immunocompromised mice

Abstract

Cryptosporidiosis is an imperative global health concern. Unfortunately, Nitazoxanide (NTZ) (the nowadays drug of choice) is not effective in treatment of immunocompromised patients. We aimed to assess the possible anti-cryptosporidial prophylactic and therapeutic effects of Mefloquine (MQ) on infected immunosuppressed murine models. Mice were divided into five groups; GI: received Mefloquine (400 mg/kg/day), GII: received NTZ (100 mg/kg/bid), GIII: received a combination, half dose regimen of both drugs, GIV: infected untreated and GV: non-infected untreated. Each treated group was divided into three subgroups; Ga prophylaxis (PX), thereafter infection, Gb first and Gc second treatment doses. Assessment was done by parasitological, histopathological and serological techniques. A significant oocyst clearance was detected in all prophylactically treated groups. GIa showed 77% reduction of the mean oocyst count in stool while GIb and GIIIc showed100% oocyst clearance. Histopathologically, the ileocecal sections from GIV showed loss of brush borders with marked villous atrophy. GIa induced a moderate improvement of those pathological changes. Moreover, the villi in GIb and GIIIc retained their normal appearance with minimal inflammatory cells. Serum interferon gamma levels showed highly significant increases in GI&GIII compared to GIV while a non-significant increase was observed in GIIa only. On the contrary, serum interleukin-17 levels showed a highly significant down-regulation in all treated groups in comparison to GIV. This study proved a marvelous effect of MQ-PX on cryptosporidiosis in immunosuppressed mice and thus it could be introduced as one of the most promising re-purposed prophylactic and therapeutic anti-cryptosporidial agents.

Keywords: Cryptosporidium; Interferon gamma; Interleukin-17; Mefloquine; Nitazoxanide; Prophylaxis.

Fig. 1

Histopathological findings of the small intestine sections (H and E): a GV (X 400) showing normal villous architecture and normal brush border. b GIV (X200) showing significant villous distortion and focal ulceration "red arrows" goblet cell hyperplasia and moderate to severe inflammatory cellular infiltration "blue arrows" Cryptosporidum oocysts appeared as rounded to oval bodies and purple stained "black arrows"

Fig. 2

Histopathological findings of the small intestine sections of GI (H and E X200): a GI a showing mild inflammatory cells in the submucosa and oedema "blue arrows". b GI b showing normal mucosa, goblet cells and returning of the normal villous pattern with no inflammatory cells

Fig. 3

Histopathological findings of the small intestine sections GII (H and E X200): a GIIa showing severe inflammatory cellular infiltrate and oedema with dilated congested blood vessels "blue arrows". b GII b showing mild to moderate Inflammatory Cells in the lamina propria, villous atrophy and goblet cell atrophy with dilated congested blood vessels. c GII c showing very mild inflammatory cells, oedema, villous and goblet cell atrophy

Fig. 4

Histopathological findings of the small intestine sections GIII (H and E X200): a GIII a showing mild villous atrophy, broad villi with moderate inflammation. b GIII b showing focal moderate villous atrophy, broad villi and mild inflammatory cells. c GIII b showing normal mucosa, goblet cells and returning of the normal villous pattern with no inflammatory cells

Fig. 5

IFN-γ serum levels in different drug regimens in prophylactic and proceeding two-week therapy

Fig. 6

IL-17 serum levels in different drug regimens in prophylactic and proceeding therapy